Electromagnet switching device in coordinate arrays



March 4, 1969 GncHl |To ETAL 3,431,519

ELECTROMAGNET SWITGHING DEVICE IN COORDINATE ARRAYS `Filed May lz, 19s? Sheet of CULUMN SELECTION SWITCH FIG. 2 '1 March 4, 1969 @ncl-u n'o ETAL ELECTROMAGNET SWITCHING DEVICE IN COORDINATE ARRAYS Z of? Sheet riled May 2, 1967 LINE March 4, 1969 G||||| |To ETAL 3,431,519y

ELECTROMAGNET SWITGHING DEVICE IN COORDINATE ARRAYS Filed may 2, 1967 sheet 3 of s 56 V159 52 o 6052 (Vig: n O o i o o 'III O o l f I o *21).

United States Patent O 1/ 63,753 U.S. Cl. 335-112 Int. Cl. H01h 67/14, 1/66 1 Claim ABSTRACT OF THE DISCLOSURE A plurality of sets of multiple straps constituting either lines or columns of a matrix consist of electroconductive magnetic straps, and act as magnetic cores. A plurality of reed switches are disposed in parallel with said electroconductive magnetic straps at cross points of lines and columns. One terminal of each of the reed switches is connected electrically and magnetically to said electroconductive magnetic straps and the other only magnetically connected thereto through a pair of magnetic yokes projecting from said electroconductive magnetic straps. A magnetic shunt is interposed `between the air gap of each reed switch and an electroconductive magnetic strap to form a magnetic straps ilux path at each cross point.

This invention relates to an electromagnetic switching device having improved winding structure wherein various components are used in common to reduce the number of required component parts.

In an electronic switching systems, a proportion of occupied space and cost of speech path devices with respect to the entire electronic exchange is extremely large. Accordingly, it is highly desirable to develop these speech path devices having a small size and improved capability.

As is well known, for the electromagnetic switching device in coordinate arrays for use as speech path devices in electronic telephone exchanges of the space division type, there have been used so-called Ferreed switches as disclosed in The Bell System Technical Journal, September 1964, No. 5, wherein a plurality of reed switches are arranged perpendicularly to a magnetic shunt plate at respective cross points on a matrix with the air gaps between contacts lying on the plane thereof. Semi-hard magnetic cores are disposed around the reed switches, in which by the change of the polarity of magnetization the -on-oi states of the reed contacts are controlled. Since the windings in this :construction are wound on respective bobbins mounted perpendicularly to said shunt plate at respective cross points, it is diilicult to wind the wire at high speed. In such a method of winding, as much as an hour is required for winding, especially when a large number of windings are required. Moreover, as the spacing tbetween adjacent cross points cannot be reduced beyond a certain limit, it is diicult to miniaturize the switching device.

It is therefore an object of this invention to provide an improved electromagnetic switching device in coordinate arrays without the accompanying difficulties mentioned above.

According to this invention a plurality of sets of elecice troconductive magnetic straps act as multiple straps of either lines or -columns of a matrix as well as magnetic cores. A rst exciting winding is wound successively around a set of electroconductive magnetic straps which are molded together with a plastic material at each cross point of lines and columns. A secondary exciting winding is wound around a plurality of molded sets of straps in a direction perpendicular to the longitudinal direction thereof. The primary and secondary exciting windings together form a differential winding.

The features of the invention which are believed to be novel are set forth with particularity in the appended claim. The invention itself, however, as to its organization together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. la is a schematic representation showing a coordinate array of electric switching elements of one embodiment of this invention;

FIG. lb is a connection diagram showing the exciting windings of the embodiment shown in FIG. 1a;

FIG. 2 is a partial view to explain a cross point element embodying this invention;

FIG. 3 is a perspective View showing an assembly of crosspoint components constructed according to this invention;

FIG. 4 is an elevational view, partly broken away, to illustrate 'various steps of fabrication of an electromagnetic switching device in coordinate arrays embodying this invention;

FIG. 5 is a rear view of the assembly shown in FIG. 4;

FIG. 6 is a side view of the assembly, shown in FIG. 4 as viewed in the direction indicated by an arrow A;

FIG. 7 is a side view, partly in section, of the .components shown in FIG. 4 as viewed in the direction indicated by an arrow B; and

FIG. 8 is an exploded view of components shown in FIG. 7 at a portion indicated by an arrow C.

Referring now to the accompanying drawings, as shown in FIG. la, a plurality of magnetic reed switches 511, 512, 51,1, 5m, 52 5mn are provided at respective cross points between multiple straps 11a, 11b, 12a, 12b, 11m, lnb and 21a, 21h, 22a, 2gb, 2113 Znb are Iespectively arranged in lines and columns to form a matrix. One terminal of each reed switch is electrically -connected to one of multiple straps constituting a line which `corresponds to an incoming, while the other terminal to another multiple strap constituting a column which corresponds to an outgoing. Said reed switches and multiple straps cooperate to form electric circuits and magnetic circuits.

FIG. lb shows the construction of exciting windings for respective reed switches arranged in a matrix as shown in FIG. 1a. Thus, for example, at respective cross points each rst winding connected to a terminal of a line selection switch l6 via respective conductors 31, 3'2, 3m comprises two portions wound on both sides of a magnetic shunt which is interposed between the air `gap of a reed switch and an electroconductive magnetic strap as shown in FIG. 2, and each second winding connected to a terminal of a column selection switch 7 via respective conductors 41, 42, 4h comprises also two portions. Said iirst and second Iwindings are each connected to a common conductor 8. These windings are wound in the well known differential manner.

The principle of the operation of this invention will now be described by referring to FIGS. la, lb and 2. As shown in FIG. 2 a pair of yokes 9a and 9b project from a multiple strap which is made of a semi-hard magnetic material and used also as a magnetic core. One terminal of a reed switch 11 is connected electrically and magnetically to the multiple through the yoke 9a, while the other terminal is connected only magnetically to the mutliple strap 10 through the yoke 9b by inserting an electrical insulator therebetween. A magnetic shunt 12 is interposed between the air gap of the reed switch 11 and the multiple strap 10. Exciting Winding 13 connected to line selection switch 6 is wound at a turns ratio of about 2:1 around two portions of the multiple strap 10 which is divided by the magnetic shunt 12. The other exciting winding 14 is wound upon the exciting winding 13 so as to provide the differential excitation mentioned above. When the same direction of remanent magnetizations in two portions is produced by the exciting current in differential windings as indicated by the solid line arrowed shown in FIG. 2, a closed magnetic path will be formed through said magnetic strap 1t), yoke 9a, the air gap of the reed switch 11 and yoke 9b. Thus, the contacts of reed switch 11 will be closed. On the other hand, when the direction of remanent magnetizations are opposite each other, as indicated by the dotted line arrow shown in FIG. 2, two closed magnetic paths are formed, one is through magnetic strap 10, shunt plate 12, reed switch 11 and yoke 9a and the other is through magnetic strap 10, shunt plate 12, reed switch 11 and yoke 9b. Therefore the lmagnetic flux through the contacts will be nearly zero.

Returning back to FIG. lb, to close the contacts of a reed switch at a cross point, for example the reed switch 5mn at the cross point of the line 11m and the column 21u, a voltage will be impressed across the terminal Em of the line selection switch 6 and the terminal En of the column selection switch 7. In this example, the reed switch 5mn will be closed, "but reed switches 5ml, 5m, 5m(n 1) on the line 11m and reed switches 51D, 52m 5(m 1m on the column 2m will be opened by the remanent magnetization on the straps produced by the differential exciting current. This completes the interconnection between the line 11n and the column 2m.

The details of the construction of an errrbodiment of this invention will now be described hereunder by referring to FIG 3. FIG. 3 represents the case of a two-wire switching network and 2 x 2 array size. As shown in FIG. 3 each set of multiple straps 10 which are made of a semihard material are electrically and magnetically connected to one reed terminal of the reed switch through yoke 9a at each cross point, and is only magnetically connected to the opposite terminal through yoke 9b. Magnetic shunt 12 perpendicular to said magnetic strap 10 is positioned between the air gap of a reed switch 11 and magnetic strap 10. An opening in the strap 10` is provided for decreasing the magnetic mutual interference between adjacent cross points. The primary winding 131 is successively wound around a set of parallel straps 1t)` at each cross point so that the turns ratio of the two portions of the primary winding 13 is about 2:1.

The secondary Iwinding 14 is wound around two adjacent sets of connecting conductors 10. As already mentioned in connection with FIGS. 1 and 2, these exciting windings 13 and 14 are wound to provide differential excitation.

As mentioned above, the on-off control of a reed switch is effected by the remanent magnetization of the semihard magnetic strap; this means the self-latching switching device. According to this invention the current-latching switching device is also possible when the straps are replaced by a soft magnetic material.

FIGS. 4 through 8 illustrate a form of a practical construction of the arrangement shown in FIG. 3 in the case of two-wire switching. FIG. 4 illustrates a plane view, partly broken away, of a switching device. A plurality of molded sets 50 in which a pair of electroconductive magnetic straps and yokes 53a, '53h are molded together with a Iplastic material and around which first winding 51 is wound, is lpiled up as shown in this figure and is fixed at both ends thereof by fixing members 58 and 59. Around the fixed molded sets, the second windings 52 are Wound. The first windings and the second windings form the differential windings at each cross point. Reed switches 55 are fixed between yokes 53a and yokes 53h after inserting the magnetic shunt 7 into spacings 54, the shunt 7 being common to the respective cross points of the direction of line. Respective terminals of the terminal group 56 are connected to the respective multiple straps of lines and columns, and to 65 one end of each rst winding and second ywindings respectively. The other ends of these windings are connected to common wire 57.

FIG. 5 is a rear view of the assembly shown in FIG. 4 and identical portions are designated by the same reference numerals. It is believed that no additional description is necessary. In this figure, numeral r60 designates multiple straps in the direction of each line.

FIG. 6 is a side view of the assembly shown in FIG. 4 as viewed in the direction of the arrow A in FIG. 4 and illustrates the arrangement of reed switches 8.

FIG. 7 shows a longitudinal sectional view of the assembly shown in FIG. 4 as viewed in the direction of an arrow B.

FIG. S shows an exploded view of the components assembled at a portion C in FIG. 7. As shown in FIG. 8, a yoke 53a connected to one terminal of a reed switch is supported upon a set of electroconductive magnetic straps 10a through an electrical insulator 20. Another yoke 53h separated from the yoke 53a is fixed and electrically connected to the electroconductive magnetic strap 10a. In this embodiment, the electroconductive magnetic strap 10a is piled upon another electroconductive magnetic strap 10b via an electrical Iinsulator 23 to lower induction noise on a speech path. The yoke 53a is connected magnetically through an electric insulator 24 and yoke 53d is connected electrically and magnetically to the strap 10b. Numeral 27 designates the opening for de-V,

creasing the magnetic mutual interference lbetween the adjacent cross points.

It should be understood that the linvention is not limited to the particular embodiment shown and described and that many modifications may be made without departing from the true spirit and scope of the invention as defined in the appended claim.

What is claimed is:

1. A coordinate array of electromagnetic switching devices comprising:

a plurality of sets multiple straps arranged on the plane of a matrix for-ming lines and columns, and a plurality of cross points, each set of said multiple straps arranged in the direction of a line being integrally molded with a plastic material;

a plurality of reed switches;

a plurality of yokes projecting from each of said multiple straps vertically with respect to the plane of said matrix at each of said cross points for supporting said :reed switches;

a first exciting winding wound successively around each set of molded multiple straps at each cross point of said matrix, said successive windings of said first exciting winding being connected in series;

means for arranging said sets of molded multiple straps to form a plurality of said l-ines;

a second winding wound around a plurality of said successively wound windings of said first exciting winding, said second winding being wound in a direction parallel to the direction of a column; and

5 means for fixing both ends of said arrangement of molded `multiple straps which form said lines, said fixing members #seing disposed substantially perpendicular to said lines.

References Cited UNITED STATES PATENTS 1/1963 Blaha 335-153 6 3,215,795 11/1965 Matthias 335--153 3,303,442 2/1967 McKeon 335-154 U.S. Cl. X.R. 

